Wheel-balancing machine



May 29, 1962 F. A. MCWHORTER 3,036,467

WHEEL-BALANCING MACHINE Filed Dec. 10, 1959 FIG.I

2 Sheets-Sheet l 64 IL E INVENTOR. F. A. Mc WHORTER BY a I a I,

ATTORNEY 3,3h,467 Patented May 29, 1962 3,036,467 EL-BALANQNG MACHEQE Fred A. MeWnorter, Davenport, Iowa, assignor to Bee Line Company, Bettendorf, Iowa Filed Dec. 10, 1959, Ser. No. 858,715 3 Claims. (Cl. 73459) This invention relates to wheel-balancing machines, especially for the balancing of automobile and truck wheels when removed from the vehicle and mounted on the machine. The principles of the invention are applicable, of course, to the balancing of other rotatable bodies, but reference herein will be had to vehicle wheels, since balancing machines for wheels of that character are generally known and many of the fundamentals of wheel balancing are familiar to those versed in the art. However, such reference is illustrative only and not limiting. Likewise, the benefits and advantages of balance wheels are well known and need not be elaborated here, except as such are improved by the present inventive machine and use thereof.

One of the more significant objects of the invention is to provide an improved wheel-balancing machine featuring a design which is based on simplicity, economy of manufacture and ease of maintenance and use. A further important object is to provide improved means for rotating the wheel at relatively high speeds when mounted on the mac 'ne. Further objects reside in improvements of the system by which the dynamic unbalance is determined and measured, improvements in the operating controls for the machine, and such other features and objects, inherent in and encompassed by the invention, as will appear as the disclosure of a preferred embodiment of the invention is made, by way of example, in the ensuing specification and accompanying sheets of drawings, the figures of which are described below.

FIGURE 1 is a plan view, with portions broken away, illustrating the overall appearance of the machine as seen from above.

FIGURE 2 is a side view of the same, with portions broken away to expose some of the control and operating parts.

FIGURE 3 is a longitudinal section through the support and spindle of the machine, drawn to an enlarged scale.

FIGURE 4 is a fragmentary plan view, on a scale enlarged over that of FIGURE 1, and showing the gaging linkage in a position different from that in FIGURE 1.

FIGURE 5 is an enlarged fragmentary view as seen generally on the line 55 of FIGURE 4.

FIGURE 6 is a section as seen along the line 66 of FIGURE 4.

FIGURE 7 is a fragmentary View, partly in section, as seen along the line 7-7 of FIGURE 5.

FIGURE 8 is a schematic illustration of the electrical circuit used in the machine.

The machine comprises essentially a base 10, having an upper fiat top or table portion 12. The top is apertured at 14 (FIGURE 3) to receive upright support means in the form of a vertical sleeve 16 having a flange 18 rigidly secured to the top 12 as by cap screws 20. The upper terminal end of the sleeve is reduced or pro vided with a shoulder on which is mounted the inner race ring 22 of a self-alining bearing 24, the outer race ring 26 of which carries a lower circular member in the formof 28. The upper surface of the member 28 is provided as a clutch or frictional face and for this purpose is equipped with an annulus of friction material at 30. Because of the self-alining nature of the bearing 24, the outer race ring 26 and the member 28 not only rotate about the upright axis of the support means 16 but also oscillate relative to the support means about a virtual point B which lies on the axis of the support 16 and which is generally in the radial plane of the self-alining bearing.

An inner upright tubular member or sleeve 32 is axially shiftably received by the support means 1-6 and has at opposite ends thereof anti-friction bearings 34 and 36, respectively, which journal a central shaft or spindle 38. Suitable means are provided in cooperation with the shaft and bearings 34 and 36 so as to secure the shaft against axial displacement relative to the sleeve 32 while per-mitting rotation of the shaft relative to the sleeve. As illustrated, these means include snap rings and locking nuts, which need not be separately designated inasmuch as they are readily visible and, further, inasmuch as many equivalents thereof could be substituted for the component shown. Suflice it to note, as already indicated, that the shaft is rotatable relative to the sleeve 32 but is capable of axial shifting with the sleeve when the sleeve is shifted within the outer sleeve or support means 16.

The shaft 38 is reduced at its upper terminal end and receives the inner race ring 40' of an upper self-alining bearing 42, the outer race ring 44 of which serves to mount a wheel-mounting member 46, the upper portion of which is in the form of a spindle 48 having a lower or intermediate tubular portion 50' which in turn is equipped with a coaxial inverted cup-shaped annulus or member 52. The lower face of the member 52' is generally congruent with the friction face 39 on the previously described member 28 and, for purposes of identification, this lower face is identified by the numeral 54.

There is sufficient clearance between the inside diameter of the tubular portion 50 of the member 46 and the outside diameter of the upper portion of the shaft 38 to permit tilting of the member 46 about an upper virtual point A, provided that the member 46 is raised sufiiciently to clear its friction face 54 from the friction face 30 on the member 28. Thus, the upper self alining bearing 42 carries the member 46 not only for rotation relative to the shaft 38 but also for universal rocking or tilting about the virtual point A. As will be described below, the member 46, together with the shaft 38, may be elevated to disengage the friction faces 30 and 54.

The lower end of the shaft 38 has rigidly keyed or pinned thereto a sheave 56 which may be belt driven in any suitable manner, as from a small electric motor 58 (FIGURE 2). This motor may be mounted on the depending lower end of the sleeve 32 via a support 60 so that the motor and sheave are shiftable with the sleeve 32 and shaft 38. The means for imparting vertical shifting to the structure just described is shown here as a pedal 62 fulcrumed on the base at 64 and connected by a link 66 to the lower end of the sleeve 32. A coil compression spring 68 acts between a lower collar 70 on the sleeve 32 and an upper nut or collar 72 on the lower threaded end of the support means 16 to urge the vertically shiftable structure downwardly, thus establishing engagement between the two frictional or clutch faces 30 and 54. Depression of the pedal will of course act .against or overcome the spring 68 so as to elevate the sleeve 32 and the shaft 38 together therewith. Since the wheel-mounting member 46 is carried by the shaft 38 via the upper self-alining bearing 42, the wheel-mounting member will also shift upwardly and the faces 54 and 30 will be separated. This will free the member 46 for tilting about the virtual point A, since the member 46 is now spaced above the surface or base 30. This is illustrated in broken lines in FIGURE 3.

The wheel-mounting member 46 is equipped with means for mounting coaxially thereon a vehicle wheel such as that represented at W. The mounting means may include appropriate locating collars and the like, such as that shown at 74, together with a securing nut 76. The

mounting is such that the wheel is fixed to the member 46 for rotation therewith. Likewise, the wheel may tilt with the member about the upper virtual point A when the structure is shifted upwardly to disengage the ciutch faces 54 and 39. In this mannerthat is, with the clutch faces 54 and 3ii disengaged-the Wheel may be checked for static balance or' unbalance, at which time any conventional gage may beused, such as the spirit-level type shown at 78. In other words, with the wheel free to tilt about the virtual point A, the level 78 may be used to determine the location of static unbalance and suitable weights may be added to the rim or the wheel, as is conventional, until the. wheel balances or levels on the virtual point A. As is customary in machines of this type, the wheel is first statically balanced before it is checked for dynamic unbalance. Another point that should be noted in connection with the static balancing procedure is that the motor 58 is energized to drive the shaft 38, thus causing the shaft to rotate relative to the wheel. The purpose of this procedure is to eliminate friction from the bearing 42 so that the static testing will be more accurate. This per se is known.

The wheel is rotated at relatively high speeds for the purpose of dynamic balancing and gaging of the dynamic unbalance by means of drive means, here in the form of an electric motor 80 which has its driving shaft upright and to which shaft is keyed a wheel spinner 82. The lower part of the motor 89 is provided with a depending pintle 84 which provides part of means for mounting the motor on the top 12 of the base 19. Another part of this means includes means providing a socket 86 on the top 12 which is receivable of the pintle $4 and which afiords a pivot on a vertical axis about which the motor may be rocked, as by means of a handle 88; Thus, the motor may have a neutral or disengaged position in which the spinner 82 is out of engagement with the tire of the wheel W, plus another position in which the spinner engages the tire, whereby the drive means is directly engageable with and disengageable from the wheel W, as distinguished from prior constructions in which motors and belts were used to drive some other part selectively clutchable to the wheel. Accordingly, the present drive system is considerably simpler and more efficient than those known in the past. Another feature of the drive means is that the motor 80 is mounted on a bracket or support 90 which in turn carries rigidly thereon braking means 92. Thus, when the motor and bracket as a unit are rocked in a. clockwise direction about the pivot axis at 848'6, the spinner 82 will engage the tire. Reverse rocking will disengage the spinner and further counterclockwise movement will bring the brake means 92 into engagement Wtih the tire to retard rotation thereof The motor 80 may be energized or deenergized, or mobilized and demobilized by a typical electrical switch 94. This is illustrated in FIGURE 8, wherein it is shown that the circuit may be connected to a source of electrical energy at 96, and the circuit includes appropriate elece163? connections to the motor 58, which is controlled by a separate switch 98. One of the lines to the'motor 80 includes a third switch 100, which is operated automatically in response to certain conditions, as will appear below.

Another feature of the motor mounting is that it is selectively changeable between a plurality of positions. In the present case, at least two difierent positions are provided and these are accomplished by the socket means 86, already described, and a similar socket means 102 which affords a second location for the drive means. The pintle 84 on the drive means may be separated from the socket 86, for example, merely by lifting the drive means until the pintle is cleared. Thereafter, the pintle may be reinserted in the second socket means 102. The two socket means 84 and 102 are rotated at difierent radial distances from the vertical axis of the shaft 38, and this arrangement enables re-location of the drive means according to the diameter of the wheel being tested. The drive means may be connected to the base as by a flexible cable 194 which includes the electrical connections for the motor St) and the electrical connection thereof into the circuit shown in FIGURE 8.

As previously described, depression of the pedal 62 will elevate the wheel and wheel-mounting member 46 so that the clutch faces 54 and 30 are disengaged. The pedal may be latched in this position by any suitable means not material here, since such means is well known to those versed in the art. The wheel is then statically balanced by the procedure outlined above, after which the motor 89 is energized by the switch 94 and the handle 38 is turned so that the spinner 82 is brought into engagement with the tire of the Wheel W, thus causing the wheel to rotate at a relatively high speed. Since the wheel is free to tilt or rock about the upper virtual point A, any dynamic unbalance therein will be reflected by a wobble. That is to say, the dynamically unbalanced wheel will tiit about the virtual point A so that the common axis of the wheel and wheel-mounting member 46 will travel in a cone having its apex at point A. With the wheel and wheel-mounting member rotating in this fashion, the pedal 62 is released so that the wheel and wheel-mounting member are lowered to their original positions, causing engagement of the clutch faces 54 and 3%. Because of the tilt in the wheel-mounting member, the radial base 54 will not be normal to the axis of the shaft 38. However, since the member 28 is mounted on the lower self-aligning bearing 24, the member 28 can tilt correspondingly so that the faces 39 and 54 are flush, even though not coaxial. Hence, the outer rim of the lower flange on the member 46 will be eccentric to the axis of the shaft 38, and it is this eccentricity that is used to gage the amount and location of dynamic unbalance, as will be presently described. With the clutch faces 54 and 30 engaged, the member 28 represents means for securing and retaining the wheel in its tilted position with its axis inclined as aforesaid.

Before gaging the dynamic unbalance, the drive means is disengaged from the wheel; that is, the motor is turned so that the spinner 82 is separated from the tire of the :heel. Hence, the wheel may berotated by hand at a relatively low speed so. that the dynamic unbalance may be measured. The measurement or determination of dynamic unbalance is accomplished by a follower, here comprising a bell crank 1G6 pivoted on the support or base at 1% and having a roller 11c which is adapted to ride the rim of the wheel-mounting member 46. During high speed rotation of the wheel and member 46, the follower is disengaged, because the high speed would ruin the bearing of the roller 110. The means for disengaging the follower comprises a link 112 having a knob 113 exposed at the front of the base, or that side of the base at which the pedal 62 is located, simply as a matter of convenience. The inner cnd'of the link is connected to a control crank 114 which is rockable on the base as by a vertical rockshaft 116. As best seen in FIGURE 2, the upper arm of the bell crank 166 is exposed above the base top 12 and the lower arm is below the base top for cooperation with the bell crank 114.

A pointer 118 is pivotally mounted at one end at 120 on an upright pivot and has its opposite end readable on a scale or indicia element 122. An arm 124, which may be regarded as an extension of the pivoted end of the pointer, is associated with the pointer in such manner that the two are spring-loaded to the position shown in FIG- URE 4. Any conventional spring may be used, as a torsion spring (not shown). When the control link 11-2 is pulled outwardly as shown in FIGURE 1, the bell crank 11 is rocked into engagement with the lower arm of the follower bell crank 166, swinging this arm in a counterclockwise direction so that the roller becomes disengaged from the lower rim of the wheel mounting member' 45. At the same time, the lower arm of the bell aosaaev crank 106 is brought into engagement with the arm 1.24, causing the pointer 118 to swing to the position of FIG- URE 1. As the arm 124 swings to the position of FIG- URE 1, it closes the switch 104), thus completing the circuit to the motor 80. This is the position that the control or gaging linkage should occupy during high-speed rotation of the wheel W by the spinner 82. As a matter of fact, the motor 80 cannot be energized when the knob 113 is pushed inwardly because that action removes the bell crank 114 from the follower bell crank, and the spring-load behind the pointer 118 or arm 1 24 causes the arm and pointer to swing to the FIGURE 4 position, thus moving the arm 124 away from the switch 100 and opening the switch, thereby breaking the circuit to the motor 80 even though the switch 94 be closed. This will be clear from FIGURE 8.

The difference between the two positions is that in FIGURE 4, dynamic unbalance will be determined by rotating the wheel slowly after it has been secured in a position in which its axis is tilted.

The indicia element 122 may be of any translucent or similar material and is shown here as being provided with three ranges of indicia, each of which may be graduated in ounces, since that unit of measurement applies to wheel weights in general. The purpose of the three ranges is to accommodate wheels of different diameters, the most popular being thirteen-inch, fourteen-inch and fifteen-inch. The method of determining the dynamic unbalance involves slowly turning the wheel, held in its tilted position by engagement between the clutch faces 54 and 30, so that the follower 110 is deflected according to the amount of tilt of the wheel. This in turn is reflected by movement of the pointer 1 18 back and forth across the element 122. The indicia in each range are disposed so that they read from zero upwardly in opposite directions from a center point, and the pointer will oscillate across the indicia to both sides of center, because of the eccentricity of the lower part of the tilted axis of the wheel and member 46. For example, the tilt may be such that the pointer will show a reading of four ounces to both sides of center, which will indicate the need for fourounce weights. The wheel is turned until the pointer centers on the zero mark, and a weight is applied to the top side of the wheel in the area of the indicating arrow 126. A similar weight is applied diametrically opposite to the weight just referred to but at the bottom side ot the wheel, so as to retain the static balance.

It is another feature of the invention to provide improved means for mounting the element 122, since this must be at times adjusted laterally to center it on the pointer. For this purpose, the front wall of the base top 12, as at 128, is provided with a slot 130 that runs lengthwise of the path of oscillation of the pointer 118. A carrier 132 is passed through the slot and is threaded into the element 122 and is free to move lengthwise of the slot. In order to releasably retain the element 122 in its adjusted position, the design includes frictional resilient means, here in the form of a coiled compression spring 134 acting between a knob 136 on the carrier and a washer which abuts the front wall of the top portion 128. An interior portion of the base is provided with a pair of supports 1.38 on which opposite ends of the element 122 lightly rest. The purpose of these supports is to prevent rotation of the element 122 about the axis of the carrier or screw 132. A top panel of transparent material, as at may be provided as a window through which the element 122 and free end of the pointer are visible.

Features and advantages of the invention, other than those enumerated herein, will readily occur to those versed in the art, as will many modifications and alterations in the preferred embodiment disclosed, all of which may be achieved without departure from the spirit and Scope of the invention.

What is claimed is:

1. In a wheel-balancing machine: support means on a vertical axis and including a coaxial bearing affording a virtual support point on said axis; a wheel-mounting member journaled on the bearing and tiltable about said point; means on the member for coaxially fixing thereto a wheel to be tested for dynamic balance or unbalance; drive means for rotating the wheel and member at a relatively high speed so that any dynamic unbalance in the wheel will be reflected by tilting of the wheel and memher on said point and travel of the axis thereof in a cone having its apex at said point; means on the support and rotatable relative thereto for securing the tilted position of the wheel and member and operative to retain said position so that the wheel and member may be subsequently rotated at a slower speed; and gage means for determining the dynamic unbalance, including a follower engageable vw'th and movable by the tilted member, a pointer connected to and movable by the follower, an indicia element cooperative with the pointer, and means mounting the indicia element on the support means for adjustment relative to the pointer in opposite directions along the path of movement of the pointer, said mounting means for the element including a part on the support means having a slot lengthwise of said path, a carrier fixed to the element and having a handle portion extending through said slot for effecting movement of the carrier lengthwise of the slot, and means for releasably holding said carrier against move ment.

2. The invention defined in claim 1, including: an abutment on the carrier spaced from said part, and said holding means includes a spring acting at one end against the part and at its other end on said abutment.

53. The invention defined in claim 1, including: means on the support means and engageable with said element to prevent rotation of the element and carrier.

References Cited in the file of this patent UNITED STATES PATENTS 2,298,656 Smith Oct. 13, 1942 2,349,552 Holmes May 23, 1944 2,792,725 Lannen May 211, 1957 2,968,185 Jacobsen Jan. 17, 1961 

